Boat Momentum Efficiency Challenge

[foamyesque]

Just now, The_Rocketeer said:

Lol, in other words you freely admit that in your 'max speed' screenshot you are literally airborne, i.e. not floating, i.e. a seaplane, not a boat.

Sure, aero lift is what's stabilizing me and lifting me in that shot. I don't argue otherwise. I'm not sure how you could have anything else at that speed, though. I suppose I could try something that doesn't use the Mk2 spaceplane parts (which have inherent lift) but at Mach 0.9 even body lift becomes pretty significant; you can see the big tails off the Goliath engines, for example.

[seanth]

In the craft I have been designing, I have stacked foils, and you can see changes in lift as my craft rise out of the water: the uppermost foil lift arrows shrink as the leave the water's surface. That makes perfect sense since I'd expect a foil to have more lift in water at low speed than in air at the same speed.

What is not at all clear to me is how that applies to big foils that are sort of vertically in water and air. @foamyesque's hydrofoil2 has those angled back wings that provide net lift up and out, and the front ones provide net lift up and in. If KSP was doing the math correctly, as those angled wings rise up in the water--and thus have less wing in the water--they should provide less lift and a given speed. Right? I suspect that KSP is seeing them touching the water and giving them water-lift values for the entire wing surface.

Edited July 22, 2016 by seanth
lift, not like

[The_Rocketeer]

1 minute ago, foamyesque said:

Sure, aero lift is what's stabilizing me and lifting me in that shot. I don't argue otherwise. I'm not sure how you could have anything else at that speed, though. I suppose I could try something that doesn't use the Mk2 spaceplane parts (which have inherent lift) but at Mach 0.9 even body lift becomes pretty significant; you can see the big tails off the Goliath engines, for example.

Well this kinda points at what I'm shooting at here. You're exceeding the bounds of what is possible with a boat by accelerating to speeds at which it ceases in all practical senses to be a boat and instead becomes a ballistic missile. In other words, this challenge or future challenges that are specifically comparing BOATS need to have sufficient rules restrictions or scoring limitations to disqualify such entries.

Not that what you've done isn't incredible, and I commend your engineering skills, but that ain't no boat.

[seanth]

3 minutes ago, foamyesque said:

Sure, aero lift is what's stabilizing me and lifting me in that shot. I don't argue otherwise. I'm not sure how you could have anything else at that speed, though. I suppose I could try something that doesn't use the Mk2 spaceplane parts (which have inherent lift) but at Mach 0.9 even body lift becomes pretty significant; you can see the big tails off the Goliath engines, for example.

I've been designing my stuff so they get up out of the water and at what I consider an ideal height when the overall lift in kN is less than the weight (in kN) of the craft. That way I am guaranteed that my ships won't become planes by mistake. My problems come when I crank up the speed and the lift increases. But that's why I stack my foils: as foils leave the water, the craft gets less lift.

[foamyesque]

9 minutes ago, seanth said:

What is not at all clear to me is how that applies to big foils that are sort of vertically in water and air. @foamyesque's hydrofoil2 has those angled back wings that provide net left up and out, and the front ones provide net lift up and in. If KSP was doing the math correctly, as those angled wings rise up in the water--and thus have less wing in the water--they should provide less lift and a given speed. Right? I suspect that KSP is seeing them touching the water and giving them water-lift values for the entire wing surface.

KSP does the math correctly; the self-stabilizing lift mechanic of the V-plough layout I use would not function otherwise. If it gave me the full lift value of those wings regardless of how much was in the water, I wouldn't be able to stay in the water at all past about 80m/s, which is when the entire body has been popped clear of the surface. Like, you can see in the 330m/s picture that the back foils are a. in the water and b. not acting like the whole foil is in the water (otherwise the ship would somersault). You asked for the craft file; take a test run and watch the aero indicators.

 

EDIT: Also, I'd be completely unable to accelerate, since the drag induced by that lift would remain constant, so the whole thing just wouldn't work at all.

Edited July 22, 2016 by foamyesque

[seanth]

Finished testing Franklin My Dear for distance (I made it to a point just northwest of the island off by itself in the Western Ocean), and started testing s new ship.

Hello eclipse. 

AND, cargo bay doors are weird in terms of drag.

[Heffy]

Okay now that I'm sober, I figured out how to fix my MechJeb...  I will let a smarter person do the math for "Make KSP Great Again".  Biggest ship I could make without crashing my game over and over again.  Took about 10 minutes to safely drive this thing to the water and keep it at a low enough speed to hold together on surface impact lol.  Might try emptying most of the tanks to see what max speed would be with no load.

 

EDIT:

Emptied most of the fuel. She now rides high and mighty out of the water, going twice the speed as before.  I'm so proud!!! *sniffle* :'D Can't see current speed in the screenshots on here. Below is link.

http://imgur.com/a/00gmm  

Edited July 23, 2016 by Heffy
Added empty voyage screenshot

[seanth]

19 hours ago, Heffy said:

Okay now that I'm sober, I figured out how to fix my MechJeb...  I will let a smarter person do the math for "Make KSP Great Again". 

Sober, calculated, and posted. That is a monster of a craft!

[Cunjo Carl]

On 7/22/2016 at 1:58 PM, The_Rocketeer said:

Lol, in other words you freely admit that in your 'max speed' screenshot you are literally airborne, i.e. not floating, i.e. a seaplane, not a boat.

On 7/22/2016 at 2:01 PM, foamyesque said:

Sure, aero lift is what's stabilizing me and lifting me in that shot. I don't argue otherwise. I'm not sure how you could have anything else at that speed....

This is totally a thing that's happening in real life, and it's amazing! Here's a charming and informative article about the crazy flying yachts that people have started racing with: http://www.theverge.com/2016/5/25/11771276/americas-cup-boat-design-team-oracle

 

Also, @Heffy, welcome to the forums! That is a sweet barge.

[The_Rocketeer]

6 hours ago, Cunjo Carl said:

This is totally a thing that's happening in real life, and it's amazing! Here's a charming and informative article about the crazy flying yachts that people have started racing with: http://www.theverge.com/2016/5/25/11771276/americas-cup-boat-design-team-oracle

@1:45 "the innovation is due to the use of hydrofoils". There is no aerodynamic lifting force involved - these boats do not fly, they hydroplane.

Edit: to be clear, I am differentiating between foils used in the medium of air to generate aerodynamic lift and foils used in the medium of water to generate hydrodynamic lift. Aerodynamic lift is aeroplaning, aka flight, hydrodynamic lift is hydroplaning aka float.

Edited August 5, 2016 by The_Rocketeer

[Cunjo Carl]

9 hours ago, The_Rocketeer said:

@1:45 "the innovation is due to the use of hydrofoils". There is no aerodynamic lifting force involved - these boats do not fly, they hydroplane.

Edit: to be clear, I am differentiating between foils used in the medium of air to generate aerodynamic lift and foils used in the medium of water to generate hydrodynamic lift. Aerodynamic lift is aeroplaning, aka flight, hydrodynamic lift is hydroplaning aka float.

On 7/22/2016 at 2:01 PM, foamyesque said:

Sure, aero lift is what's stabilizing me and lifting me in that shot. I don't argue otherwise. I'm not sure how you could have anything else at that speed....

Oh, now that I read through the last couple pages of the challenge I should have picked up on that. I was just so excited about flying boats. And yes, as you say these use the hydrofoils primarily to lift them out of the water (and to keep the aerolift, which they can also get plenty of, from accidentally flipping them out of the water as I understand it!)

Hm. I don't think I'll set any bars, but this challenge sounds interesting.